Two problems with that pull down device:
1. Since it can be 'easily overcome by the pilot' if you are frozen in fear at the engine failure it probably won't overcome you.
2. If, as many seem to manage, you make an approach to a high hover and overpitch enough to droop the RRPM (not enough power available) - at the point where a gentle lowering of the lever might save you and allow a gentle descent regaining RRPM - the pull down device activates and you are fighting that too as it tries to get the lever on the floor.
The answer is to keep current on autos so the muscle memory kicks in - practice isn't just for the sorties leading up to your PPLH.